Genome

3 Key excerpts on "Genome"

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  eBook - ePub

  The Encyclopaedia of Sports Medicine, Genetic and Molecular Aspects of Sports Performance

  • Claude Bouchard, Eric P. Hoffman(Authors)
  • 2011(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  http://www.Genome.gov/ ), was invented for the purpose of naming a new genetics journal and was coined in 1986, by one of its founding editors, Dr Thomas H. Roderick, of the Jackson Laboratory, Bar Harbor, ME. Genetics and genomics can be considered synonyms, with genomics being trendier, implying something new, modern, and big, and embracing the entire anatomy and physi ology of all human genes, including the elements that control the action of genes (i.e., turning them on and off). “Genome” is traced to Hans Winkler in 1920, referring to the entire set of genes in a germ cell (sperm or ovum) (Yadav, 2007). Human genomics is the study all human genes acting together over a lifespan.

  The gene is the basic physical–chemical unit of inheritance, consisting of the famous deoxyribonucleic acid (DNA), configured as a double helix of paired complementary strands, as deduced by Watson and Crick in 1953. The total DNA of a single cell is approximately 2.5 m in length (if stretched out straight) and 3 billion base pairs. Considering that an estimated 100 trillion cells make up the human body, the amount of DNA is massive. DNA encodes instructions for the development and function of the entire human being, producing the nickname, the “blueprint of life.” The definition of a gene was, until the HGP, a piece of DNA that encodes the amino acid sequence of a single protein, hence the cliché, “one gene—one protein,” and the estimated total of 100,000 genes, the numbers of distinct human proteins. When the entire sequence of all nucleotides found in all nuclear DNA was analyzed, the definition of a human gene has become a physical– chemical one, based on the typical structure of a human gene (Figure 1.1 ). The estimated number of human genes has been revised downward to 25,000, with the realization that each stretch of DNA can code for an average of three proteins.

  Figure 1.1

  Visual outlay of genetic materials starting at the level of the cell and finishing at the level of nucleotide base pairing.

  Genes are passed from parents to offspring and contain the information needed to specify physical, biochemical, and behavioral traits. Genes are arranged, one next to another in a linear fashion, on structures called chromosomes. A chromosome contains a single, long DNA molecule, only portions of which correspond to single genes. This organization results in all 25,000 human genes being arranged on 23 pairs of chromosomes in the cell nucleus, in addition to 37 genes which are located in the mitochondria in the cell cytoplasm.

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  Who Owns You?

  Science, Innovation, and the Gene Patent Wars

  • David Koepsell(Author)
  • 2015(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  It is not an exaggeration to say as I have earlier that the Genome, interacting with its environment, is a sort of very complex Turing machine. It codes information enough to conduct every single process, from development through metabolism and reproduction, all with the aide of other molecules, including enzymes, various forms of RNA, proteins and the inter- and intracellular environments, all of which are likewise coordinated by the information encoded in the organism’s DNA. It is the structure of DNA that enables it to direct all other functions and processes throughout the organism, as well as to replicate both from one generation to the next, and within the body as necessary to perpetuate both the species and the individual. The ultimate form of an organism is directed at the molecular level by the sequence of bases with input from the environment. There are numerous and ongoing intermediate steps from the level of the basic information to expression in the form of the organism, and various opportunities for things to go wrong. In other words, each organism has its prototypical form, as expressed in the bulk of its members, and its particular form, as expressed by its particular genetic makeup in combination with the environment. Some individuals exhibit pathological features. This is a good juncture to get clear on some terms and concepts that will recur, and which cause actual confusion in other discussions of these ideas, namely, “expression” and “environment.”

  “Expression” is not an Expression

  Ordinarily, the term “expression” connotes intention. For instance, I (Koepsell) have argued that all man-made objects intentionally produced are expressions and vice versa. Thus, it is technically inaccurate to discuss biological phenomena, which are typically not the result of human intention (except through genetic engineering), as somehow “expressions.” Yet this is the biological terminology. It would be more philosophically accurate to call the phenotype and its features “end results” of the genotype rather than expressions because an end result does not imply teleology (intention). Throughout this text, however, we will use the typical biological term and ignore its troubling philosophical implication except when otherwise necessary for the argument.

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  Exploration and Analysis of DNA Microarray and Other High-Dimensional Data

  • Dhammika Amaratunga, Javier Cabrera, Ziv Shkedy(Authors)
  • 2014(Publication Date)
  • Wiley

    (Publisher)

  Chapter 2

  Genomics Basics

  It is useful to review the basic concepts of modern molecular biology before fully immersing ourselves in the world of microarrays. We are sure that readers who have had limited exposure to this fast-developing field would appreciate this review, others may skip ahead. Genomics is a fascinating subject; after all, it is the story of life, and can occupy a multivolume book just by itself. In the interest of space, of course, it is necessary that we confine our discussion to those topics that are essential to an understanding of the science underlying microarrays, leaving other topics for interested readers to explore on their own. Some excellent general references that we, not being trained as molecular biologists ourselves, have found useful are listed at the end of the chapter.

  2.1 Genes

  From ancient times, it was suspected that there existed some sort of a hereditary mechanism that carried information from parent to child. It is because of this mechanism that family members tend to exhibit similar characteristics or traits. For example, they tend to resemble each other in terms of appearance and physical characteristics such as skin color; they tend to be predisposed toward certain diseases such as diabetes, cancer, and heart disease; and so on. However, inheritance is clearly not a perfect copying process. For example, a child of brown-eyed parents could turn out to be blue-eyed. Despite the efforts over the years of many leading scientists and thinkers to understand the hereditary mechanism, its precise nature remained an intriguing mystery until quite recently.

  Following centuries of speculation and research, the existence of discrete hereditary units, which we now call genes, has been firmly established. Each gene, either by itself or in combination with some other genes, provides a clear and unambiguous set of instructions for producing some property of its organism. The complete set of genes in an organism, essentially the master blueprint for that organism, is referred to as its Genome

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